河南“21.7”极端暴雨过程天气尺度系统发展维持机制分析  

Analysis of the mechanisms for development and maintenance of synoptic-scale weather systems during the 19—21 July extreme heavy rainfall in Henan,China

作　　者：齐道日娜 王秀明[1] 俞小鼎[1] 张军辉 Chyi Dorina;Wang Xiuming;Yu Xiaoding;Zhang Junhui(China Meteorological Administration Training Centre,Beijing 100081,China;Department of Meteorology Service,Yantai International Airport,Yantai 265617,China)

机构地区：[1]中国气象局气象干部培训学院,北京100081 [2]烟台国际机场气象服务科,烟台265617

出　　处：《气象学报》2023年第1期1-18,共18页Acta Meteorologica Sinica

基　　金：国家自然科学基金项目(41875058、42275013);中国气象局短时临近预报教学科研团队项目;中国气象局气象干部培训学院青年科研项目(2022CMATCQN03);中国气象局创新发展专项(CXFZ2021J029)。

摘　　要：利用实况资料和ERA5再分析资料对“21.7”河南极端暴雨过程的锋生作用、大气非绝热加热和水汽净收支进行了深入分析,揭示此次过程天气尺度系统发展维持机制。结果表明:本次极端暴雨过程中,河南位于西北太平洋副热带高压(副高)和大陆高压之间的鞍型场中,低层辐合高层辐散的配置有利于500 hPa低压系统的发展和维持;锋生作用主要发生在对流层低层且与θ_(se)密集区有较好的对应关系,水平散度项和水平变形项起主导作用,两者的贡献基本相当;视热源(Q_(1))和视水汽汇(Q_(2))水平分布与强降雨落区较为吻合,二者的垂直分布有明显差异,Q_(1)最强加热作用在对流层中高层,而Q_(2)垂直分布较为均匀但强度明显小于Q_(1),Q_(1)中位温垂直输送项起主导作用,而Q_(2)中比湿水平平流项发挥着主导作用,这表明本次河南极端暴雨中,区域性强凝结潜热的释放对降水有正反馈作用。伴随来自台风烟花(2106)北侧偏东气流的不断加强西进,强风速切变及地形抬升引发异常强盛的边界层水汽辐合,总水汽收支主要受到东西向水汽净流入的主导,偏东路径边界层极强的水汽输送对极端暴雨过程的维持和加强起到十分关键的作用。The frontogenesis,atmospheric diabatic heating and net water vapor budget are analyzed to reveal the development and maintenance mechanism of the synoptic scale system of the Henan province extreme heavy rainfall from 19 July to 21 July in 2021using automatic weather station observations and the fifth-generation European Center for Medium-Range Weather Forecasts atmospheric reanalysis data.Results show that Henan is located in the saddle area between the Northwest Pacific Subtropical High(NPSH)and the continental high.In this situation,the convergence in low levels is collocated with the divergence at high levels,which is conducive to the development and maintenance of the low-pressure system at 500 hPa during the extreme heavy rainfall.The frontogenesis mainly occurs in the lower troposphere and is consistent with the θ_(se) intensive region.The horizontal divergence term and horizontal deformation term play equally important leading roles in the frontogenesis.The horizontal distribution of the apparent heat source(Q_(1))and moisture sink(Q_(2))coincide with the area of heavy rainfall.However,vertical distributions show significant differences between Q_(1)and Q_(2).Q_(1)features an obvious single peak structure with the heating center in the middle and upper troposphere,while the large value area of Q_(2)is evenly distributed at 850—400 hPa.Q_(1)is larger than Q_(2)in the middle and upper troposphere.The potential temperature vertical transport term dominates in Q_(1)and the specific humidity horizontal transport term dominates in Q_(2),indicating that the release of regional-scale strong condensational latent heat has a positive feedback effect on the precipitation.With the continuous strengthening of the easterly air flow from the north side of typhoon In-Fa(2106),the strong wind shear and orographic uplift lead to an abnormally strong convergence of water vapor in the boundary layer.The net inflow of water vapor from the east and west dominates the total water vapor budget.The extremely strong water vapor

关 键 词：极端暴雨 锋生函数 视热源和视水汽汇 水汽收支 

分 类 号：P426[天文地球—大气科学及气象学]